Commitments and Contingencies - Estimated Amounts of Regular, Discharge Payments Expected to Pay and Estimated Recoveries from Charged-off Loans (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Summary Of Projections Of Estimated Payments And Recoveries [Line Items]
Estimated Regular Payments	$ 55,653
Estimated Discharge Payments	75,194
Estimated Total Payments	130,847
Estimated Recoveries	(4,911)
2013 [Member]
Summary Of Projections Of Estimated Payments And Recoveries [Line Items]
Estimated Regular Payments	9,009
Estimated Discharge Payments	0
Estimated Total Payments	9,009
Estimated Recoveries	(1,011)
2014 [Member]
Summary Of Projections Of Estimated Payments And Recoveries [Line Items]
Estimated Regular Payments	14,251
Estimated Discharge Payments	0
Estimated Total Payments	14,251
Estimated Recoveries	(1,200)
2015 [Member]
Summary Of Projections Of Estimated Payments And Recoveries [Line Items]
Estimated Regular Payments	16,060
Estimated Discharge Payments	0
Estimated Total Payments	16,060
Estimated Recoveries	(1,200)
2016 [Member]
Summary Of Projections Of Estimated Payments And Recoveries [Line Items]
Estimated Regular Payments	16,333
Estimated Discharge Payments	0
Estimated Total Payments	16,333
Estimated Recoveries	(1,200)
2017 and Later [Member]
Summary Of Projections Of Estimated Payments And Recoveries [Line Items]
Estimated Regular Payments	0
Estimated Discharge Payments	75,194
Estimated Total Payments	75,194
Estimated Recoveries	$ (300)